Semiconductor microstructures have been fabricated from strained semiconductor membranes. These strained semiconductor membranes can be grown on substrates using standard deposition techniques and subsequently patterned using standard lithographic techniques. The strain creates a curvature in the membrane such that when the membrane is released from the substrate upon which it is grown, the membrane curves and rolls up into various types of microstructures, including microtubes. The techniques referenced above can be used to produce highly regular, highly reproducible arrays of semiconductor microstructures having a variety of shapes and dimensions.
Various uses for semiconductor microtubes have been contemplated, such as freely distributed wireless sensors and drug delivery devices. It has also been shown that certain semiconductor microtubes exhibit optical activity. In particular, photoluminescence measurements of certain semiconductor microtubes have shown that some semiconductor microtubes form optical ring resonators.
However, significant impediments to realizing the potential of optically active semiconductor microtubes include the challenges of providing frequency selective feedback and engineering semiconductor microtubes with sufficient feedback and gain such that the microtube is capable of functioning as a true laser.